I have a 2001 Z06 with a K&N CAI. The other day when cleaning the filter I decided to descreen my MAF. I logged my car with OBD2 scan tool to check the LTFT's before and after the MAF screen was removed. There was a small difference (about 2%) difference in my LTFT's due to the removed MAF screen. This could have easily been due to the air temperature. Anyway, basically it did nothing bad to my car.

Soooo THEN I was reading that if you descreen your MAF on an 01 Z06 you should tune the PCM with the 02 Z06 MAF tables. So I got out my LS1_edit and copied an 02 MAF table into my pcm. Then I hooked up my scan tool and started to log as i drove around town. MY LTFT's at part throttle and idle went from 0 - +4%(01 MAF table) and jumped to +10% - +12% at part throttle and idle conditions. This also caused my PCM to add more fuel when going into power enrichment mode negating all of the tuning I had done to grab a few more HP. Even at full throttle the LTFT's were showing +8% - +10%!!

Looking at the 02 MAF table compairdto the 01 MAF table, the 02 maf table actually reports less air at a certain point(part throttle from what i could tell) then the 01 maf, then as you get into full throttle the higher frequencys report more air then the 01 MAF table. This would probably explain the LTFT's at part throttle and why the car felt a little slugish up top with the 02 maf table.

Today I am going to go log my car again to make sure the 01 maf table corrected the LTFT's. I have a sneaky suspision that the LTFT's are back in line. And I could feel it last night, it was just SCREAMING from 4400 rpms till redline. I am an experienced LS1/LT1 edit user and i adjusted the spark and PE tables for more power between 4400-6800. But it almost felt slower with the 02 MAF table not to mention I could see it was dumping alot more fuel then it should have been. ( the 02 MAF table commanded more fuel at WOT and the LTFT's were adding 10% more fuel at WOT, the car felt slugish. Uploading my stock 01 Z06 maf table to my PCM while keeping the timing and PE tables I edited the same made the car feel grat last night.

Sorry about the long post, but I felt I should share my experiences and tests on this subject. Especially since this is the forum where it was recomended to use an 02 Z06 MAF table for my descreened 01 z06 maf. I have come to the conclusion the MAF table difference in the 02+ Z06's ahs nothing to do with the screen being removed and MORE to do with the additional HP the 02+ cars make due to the cam/intake/exhaust.

I will post my findings later today when I data log the car again today.

 

Thanks, it's refreshing to see some hard data for a change.

 

A point to remember, the LTFT's refresh themselves every 10 minutes of run time. You need about 200 mile drive or 40 starts to fully update PCM changes and reactions. As you continue to log your runs, you should see more changes to the better with the 02 tune over the 01. GM found less than 2hp with the change but updated the PCM for the trims. decel and idle issues.

 

Thanks for the input, I am not done testing yet. But a little info on my data logs.....

I data logged my car with the 02 MAF table approx. 100 miles AFTER I uploaded the 02 MAF table to my pcm. Its not like i uploaded it, then turned around and logged right away. That is the same reason I havent logged my car in the past few days. I uploaded the 01 MAF table back to the car about 75 miles ago and I plan to data log it today to see where my LTFT's are and then compair the data.

I would agree with you about hte 01 vs 02 MAF to a certain extent. I can clearly see the lower maf frequency's was adjusted for ide/part throttle like you said. But after about 100 gms/sec the MAF table scales up adding MORE fuel then the 01 MAF table at WOT. Its not alot of fuel, but I believe this upward scale is due to the 02+ Z06's making a few more HP then the 01's

I have noticed NO difference in idle or part throttle driveability using either of the MAF tables. I am about to go data log right now. I will report back later today. I have a few places to go today and plan to datalog them all.

I welcome any outside information or opinions to this thread. I am only stating my findings and what I think is true. But I could be proven wrong.

Thanks,
-taz

 

Ok after a brief check of my LTFT's at idle and part throttle the 01 MAF table has reduced them to about +3% - +5% and a peak of +8 % at one point. Which can most likely be contributed to my K&N intake on the car. But is well within the normal specs.
This is considerably better then the +10% - +14% and a peak of +16% LTFTs I was seeing with the 02 MAF table.

So in the end my 01 MAF descreened but keeping the stock 01 MAF table is the right thing to do in my opinion. And for those of you who wonder about descreening your MAF I will give you the following advice.

IF you car is stock, you wont feel a difference in power, you also shouldnt have any issues with the PCM. You may however experience lower gas mileage due to the increased LTFT's descreening the MAF has. If you are good at LS1_edit or HPtuners you can adjust your VE table to compensate. But again, all this for what? 1-2 HP ?

If your car is NOT stock (heads/cam) I dont see why you should even bother leaving the screen in. You will benefit from more airflow. But you will need to tune your PCM obviously.